Computer Hardware

Form Factor

Definition

In computing, the form factor is the specification of a motherboard – the dimensions, power supply type, locations of mounting holes, number of ports on the back panel, etc.

Why It Matters

The form factor determines the physical compatibility of components. Your motherboard's form factor must match your computer case, and it influences how much space you have for other components like graphics cards and coolers.

Contextual Example

ATX is the most common form factor for desktop PCs. Micro-ATX and Mini-ITX are smaller form factors used for building more compact computers.

Common Misunderstandings

  • The term is also used for other components, like the form factor of a hard drive (e.g., 3.5-inch for desktops, 2.5-inch for laptops).
  • Choosing a form factor is one of the first decisions when building a PC.

Related Terms

Last Updated: December 17, 2025